1. Field of the Invention
The present invention relates to a system for driving display devices and, more particularly, to a device for driving memory in a display device and a method of controlling driving operations.
2. Description of the Related Art
Recently, a demand for mobile equipments, such as mobile phones and Personal Digital Assistants (PDAs), is greatly increased. Accordingly, there has been an increased demand on display devices for the mobile equipments. The display devices have a display driver for driving a display panel including Thin Film Transistors (TFTs). Generally, the display driver has memory cells for storing data, and the data stored in the memory cells is output to the display panel with a regular interval. In order to properly drive a display driver, a collision between a data read/write operation and a scan operation must be prevented. Here, the data read/write operation is performed by reading/writing data from/into the memory cells, and the scan operation is performed by transmitting the data of the memory cells to a display panel.
FIG. 1 is a view showing a memory cell of a conventional display driver. The memory cell of FIG. 1 has a dual port structure in which a write processing block 101 and a scan processing block 103 are separated from each other. The write processing block 101 includes two transistors MN11 and MN12 for transmitting data of a pair of bit lines BL and BLB in response to a word line drive signal WLD, and four transistors MP11, MN13, MP12 and MN14 for latching transmitted input data. The scan processing block 103 includes two transistors MN15 and MN16 for scanning latched data in response to a scan signal SA. That is, in the memory cell of FIG. 1, a circuit in which an operation of writing/reading data to/from memory cells is performed, and a circuit in which a scan operation of outputting the data of the memory cells to a display panel is performed, are separated from each other. Accordingly, a data collision between the two operations is prevented.
However, the conventional display drivers have drawbacks in that the memory cell of a conventional display driver is composed of eight transistors as shown in FIG. 1. As a result, the conventional display drivers necessitate a large layout area.